Method and device for hot-dip coating of metal protective layer on inner wall of metal pipe

By setting an alternating magnetic field on the outer wall of the seamless steel pipe to generate vortex current, the problems of uniformity of the hot-dip galvanized layer and redundant metal removal of the inner wall of the steel pipe are solved, and the uniformity and thickness of the plating are controlled, extending the service life.

CN119144916BActive Publication Date: 2025-05-13UESTC (SHENZHEN) ADVANCED RES INST
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Patent Information

Application Number
CN202411468221.1
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2024-10-21
Publication Date
2025-05-13
Estimated Expiration
2044-10-21

AI Technical Summary

Technical Problem

The prior art is difficult to uniformly form a hot dip galvanized layer on the inner wall of seamless steel pipes, and it is difficult to effectively remove the residue of redundant metal zinc and zinc solutions, resulting in a low service life of the galvanized layer.

Method used

By setting two sets of alternating magnetic fields perpendicular to each other on the outer wall of the metal tube, vortex current is generated to maintain the plating metal as liquid, and generate thrust to drive the redundant metal to flow out of the steel tube, thereby achieving control of the uniformity and thickness of the coating.

Benefits of technology

The uniformity of the hot-dip metal coating protective layer in the inner wall of the metal tube is improved, redundant metal is removed, the service life of the galvanized layer is extended, and the thickness of the plating is accurately controlled by adjusting the alternating current.

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Abstract

The present invention provides a method and device for hot-dip metal coating on the inner wall of a metal tube, belonging to the technical field of hot-dip metal coating. The method places the metal of the metal coating in the metal tube by hot-dip coating, and generates an eddy current on the inner wall of the metal tube that can maintain the coating metal in a liquid state. The eddy current can also generate thrust to drive the redundant metal in the liquid metal coating to flow out of the steel tube; the eddy current is formed by two sets of mutually perpendicular alternating magnetic fields arranged on the outer wall of the metal tube. The present invention forms an eddy current in the hot-dip metal coating on the inner wall of the metal tube by setting two sets of mutually perpendicular alternating magnetic fields. The eddy current acts on the coating metal, maintains the coating metal in a liquid state, and drives the redundant metal in the metal coating to flow out of the steel tube, thereby achieving uniformity of the hot-dip metal coating on the inner wall of the metal tube and accurately controlling the thickness of the metal coating; there is no need to set a scraper and compressed gas that can penetrate into the metal tube, and the operation is convenient and efficient.
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Citation Information

Patent Citations

  • Electromagnetic zinc-plating method for hot galvanizing of steel wire or steel pipe

    CN104233153A

  • Electromagnetic internal wiping device for tubular workpiece

    CN111876712A

  • Electromagnetic wiping device for coating of hot-dip galvanized steel pipe

    CN116752065A